Abstract: To identify the chromosomal location associated with powdery mildew resistance gene，the segregation of resistance was evaluated in BC2 population derived from a cross between the resistance melon PMR6 and the susceptible melon Hami413. Genetic analysis showed that the resistance to Podosphaera xanthii race 1 was controlled by one single dominant gene in BC2 population，and the gene was named Pm-PMR6-1. Among 390 simple sequence repeat（SSR）markers distributed on 12 linkage groups，5 polymorphic markers were identified by Bulked segregant analysis（BSA）. The resistance gene was located on linkage group Ⅻ between SSR markers SSR12407 and SSR12202，and the physical distance was 226 kb according to the melon genome database. Thirty-five candidate genes were predicted in this region. The resistance gene Pm-PMR6-1 co-segregated with SSR marker Mu7191 in 255 BC2 progeny. The candidate genes in this region provide a potential target site for further fine mapping and cloning of powdery mildew resistance gene in melon PMR6.

Key words: Cucumis melo, Podosphaera xanthii race 1, SSR, resistance gene